A current three-dimensional displaying technology is mainly a binocular stereoscopic parallax displaying technology. The binocular stereoscopic parallax displaying technology enables the left and right eyes of an observer to see left and right images with a certain parallax of an image pair, respectively, so that the observer can see a three-dimensional image. That is, the binocular stereoscopic parallax displaying technology separates an image signal of a picture of a stereoscopic image into left-eye image data and right-eye image data. When an image signal corresponding to the left-eye image data is displayed, the observer identifies the image signal corresponding to the left-eye image data with the left eye. When an image signal corresponding to the right-eye image data is displayed, the observer identifies the image signal corresponding to the right-eye image data with the right eye. Therefore, the observer can identify the stereoscopic image.
Because an image displayed by using a binocular stereoscopic parallax displaying technology is planar, the displayed image cannot be integrated with a realistic environment. In addition, an observer can see a stereoscopic image only by wearing dedicated stereoscopic imaging glasses. Moreover, when a binocular stereoscopic parallax displaying technology is used, to see a displayed image an observer needs to place a focus point of two eyes on a display screen of a displaying apparatus. But to identify a stereoscopic image according to the displayed image, the observer does not place a convergence point of lines of sight of the two eyes on the display screen. Because a focus point of two eyes of an observer is not on a same plane as a convergence point of lines of sight, a visual disorder and visual fatigue may be easily generated.
To sum up, an image displayed by using a binocular stereoscopic parallax displaying technology cannot be integrated with an environment. Moreover, when a binocular stereoscopic parallax displaying technology is used, an observer can see a stereoscopic image only by wearing dedicated stereoscopic imaging glasses. In addition, when a binocular stereoscopic parallax displaying technology is used, a focus point of two eyes of an observer is not on a same plane as a convergence point of lines of sight. Therefore, a visual disorder and visual fatigue may be easily generated.